This invention relates to a semiconductor device having a structure provided with contact holes and wiring grooves in an insulating film, and a method for manufacturing such a semiconductor device.
At present, a wiring comprising Al as a main constituent material is employed in a semiconductor device. In particular, the wiring most popularly employed is manufactured by a process wherein a barrier film for inhibiting the Al film from reacting with an underlying layer is formed under an Al film, or a antireflection film for inhibiting the irregular reflection of light at the occasion of lithography is formed on an Al film, and then these laminated films involving the Al film thus deposited are etched by means of RIE. Further, with an increase in integration density of LSI, the wiring is now demanded to be formed into a multi-layer wiring structure, thus necessitating a development of a plug-forming technique for making a connection between an upper wiring and a lower wiring.
On the other hand, with an increase in integration density of semiconductor devices, the wiring becomes increasingly fine, resulting in an decrease in cross-sectional area of the wiring and hence in an increase in wire resistance. Moreover, the distance between each wirings becomes narrower, resulting in an increase in inter-wiring capacity.
Such increases in wire resistance and in inter-wiring capacity lead to an RC delay, thus hindering the operation of LSI. With an increase in fineness of LSI, a multi-layer wiring is becoming more important as a factor for determining the operation speed of LSI. Therefore, the lowering in resistance of wiring as well as the lowering of dielectric constant of interlayer insulating film are now urgently desired.
As one of the conventional plug-forming techniques, W (tungsten)-CVD technique is known to be excellent in step coverage. FIG. 1A shows a cross-sectional view of the conventional multi-layer wiring structure which has been formed by making use of the W-CVD technique. In FIG. 1A, the reference numeral 81 denotes an interlayer insulting film, 82 denotes a W plug and 83 denotes an Al wiring.
This W-CVD technique can be classified into two kinds, i.e. xe2x80x9cblanket depositionxe2x80x9d and xe2x80x9cselective depositionxe2x80x9d. The xe2x80x9cblanket depositionxe2x80x9d is a method wherein a W film is deposited all over a substrate including the inner surface of contact holes. On the other hand, the xe2x80x9cselective depositionxe2x80x9d is a method wherein a W film is deposited selectively only on the bottom surface of contact holes.
Both methods are performed under a thermal condition which is different from each other. In the case of the xe2x80x9cselective depositionxe2x80x9d, the interior of the contact holes can be filled with a W film in a single step. Whereas, in the case of the xe2x80x9cblanket depositionxe2x80x9d, an etch-back step or a CMP step is required as a post treatment for removing part of W film which has been deposited outside the contact holes.
The W plug formed by making use of the aforementioned W-CVD technique is accompanied with problems that it is high in resistance and poor in EM (electromigration) resistance.
The EM is a phenomenon where Al atoms in an Al wiring are caused to move due to the collision thereof with electrons as an electric current is passed through the Al wiring. W is a material which is more resistive to EM as compared with Al. When an upper Al wiring and a lower Al wiring are connected with each other through a W plug, an accumulation of Al atoms takes place at the upstream side of the flow of Al atoms while a depletion of Al atoms takes place at the downstream side.
The accumulation of Al or depletion of Al of this kind may give rise to the generation of hillocks or voids, thus leading to a short circuit between wirings or a disconnection of wiring.
Further, in the case of the xe2x80x9cblanket depositionxe2x80x9d, part of W film which has been deposited outside the contact holes is required to be removed, thus leading to an increase in number of manufacturing step. On the other hand, in the case of the xe2x80x9cselective depositionxe2x80x9d where a step of removing W film deposited outside the contact holes is not required, the selectivity of deposition is frequently deteriorated at present so that a step of RIE etch-back is also required subsequently.
As an alternative plug-forming technique, an Al reflow technique is also known wherein a plug is formed by making use of Al which is lower in resistance than W. This method is featured in that it takes advantage of the fluidity through the surface diffusion of an Al film. This method is advantageous in that the interior of the contact hole can be filled with Al by simply heating a substrate, thus making it possible to decrease the number of the manufacturing step.
As a result of extensive studies, an underlying layer made for instance of Ti (titanium) which is excellent in wettability in relative to Al is frequently employed in the deposition of Al film. Furthermore, a two-step reflow method, wherein Al is sputtered at first without heating and then Al is sputtered again under a heated condition, is increasingly employed at present, since it is possible with this method to lower the fluidization temperature and to fill even a contact hole of high aspect ratio (A.R.) (aspect ratio=depth of contact hole/pore diameter of contact hole).
Additionally, there have been various proposals wherein a reflow technique is combined with a sputtering technique of high directivity, such as a low pressure-long distance sputtering, a collimation sputtering and an HDP (high density plasma) sputtering.
On the other hand, there is a problem in the aforementioned Al reflow technique that it is very difficult with this method to effectively fill a contact hole of high A.R. with Al. Since the Al reflow technique is based on sputtering, it is inherently poor in step coverage.
Thus, the film thickness of Al becomes relatively thin at the bottom portion of contact hole, and the Al may be agglomerated when it is heated for fluidization, generating voids in the Al film buried in the contact hole. For the purpose of overcoming this problem, a material such as Ti which is excellent in wettability to Al is employed as an underlying film as mentioned above, whereby preventing the agglomeration of Al.
However, when an underlying film is formed by a sputtering of Ti, an over-hang may be caused to develop at the opening portion of the contact hole, and the surface of Ti thus formed may become rugged. This rugged surface can be ascribed to the crystal face dependency of the crystal growth of Ti. The over-hanging of Ti as well as the rugged surface of Ti prevents not only the adhesion of Al but also the reflow property of Al. Moreover, even if a directional sputtering of Ti is employed, it is almost impossible to deposit a sufficiently thick Al film on the side wall of contact hole according to the current technique.
Further, since Ti is reactive to Al, an Al3Ti film is formed on the bottom of contact hole, and this Al3Ti film may become a cause for deteriorating the EM resistance of the Al plug as in the case of the W plug.
The application of the Al reflow technique to a damascene structure or a dual damascene structure is recently studied. FIG. 1B illustrates a cross-sectional view of the conventional dual damascene multi-layer wiring structure which has been formed by making use of the Al reflow technique. In FIG. 1B, the reference numeral 84 denotes a Ti/TiN laminate film, 82 and 83 denotes an Al3Ti film.
This dual damascene structure (DD structure) can be obtained by a process wherein contact holes and wiring grooves are formed in advance in an insulating film, and, after the interiors of these contact holes and wiring grooves are concurrently filled with Al film in a single step, any excessive externally exposed Al film is removed by means of CMP (chemical mechanical polishing), whereby simultaneously forming Al wirings and Al plugs. It is possible, according to this dual damascene structure, to simplify the manufacturing process and to save the manufacturing cost.
However, when a Ti film is employed as an underlying film and the Al-DD structure is formed by making use of the Al reflow technique, the Al3Ti film may be formed also on the inner surface of the wiring grooves, since the wiring grooves are disposed at the upper portion of the contact hole. Since Al3Ti is high in electric resistance, the formation of Al3Ti within the wiring may invite a reduction of the effective volume of the Al film and an increase in wire resistance. This problem becomes more serious as the width of wiring becomes increasingly narrow.
As explained above, there have been proposed various kinds of plug-forming technique for filling a contact hole of high aspect ratio with a conductive material. Among them, the Al reflow technique is directed to the formation of a dual damascene structure. However, when the dual damascene structure is formed by making use of the Al reflow technique, Al3Ti is caused to be formed due to a Ti/TiN laminate film to be employed as an underlying film, thus giving rise to the problem of an increase in wire resistance.
Aside from the aforementioned conventional methods, a method of covering a step portion (overhang portion) through a substitution between an Si film and an Al film has been proposed (Japanese Patent Unexamined Publication S/60-46024).
This method is known to be excellent in step coverage and can be performed by making use of the Si-CVD technique which has been employed in the manufacture of an LSI. Namely, according to this method, the overhang portion is covered in advance with an Si film, an Al film is then deposited on the Si film by means of sputtering, and the resultant layers are heat-treated thereby substituting the Al film for the Si film.
According to this method, it is possible to perform the covering of an overhang portion with an Al film, which could not be realized if only a sputtering method is employed, or to perform the filling of a contact hole of high aspect ratio with an Al film.
However, if the quantity of Si diffused into the Al film exceeds over the solid solution limit (the extent of solid solution) thereof in this method, an Si nodule (precipitation) may be formed at another location. If this Si nodule is formed within a wiring, it may become a cause for increasing the electric resistance of the wiring, and if this Si nodule is formed between wirings, it may become a cause for a short circuit between the wirings.
For the purpose of minimizing the development of Si nodule, there has been proposed a method wherein a Ti film is formed on an Al film, and then the Si diffused into the Al film is allowed to be trapped by making use of the Ti film (Japanese Patent Unexamined Publication S/63-70455).
According to this method, since the Si in the Al film can be absorbed by the Ti film, it is possible to suppress an increase in resistance of an Alxe2x80x94Si alloy wiring due to the Si nodule that may be generated at the bottom of contact hole during a heat treatment.
This method however is accompanied with a problem that since Ti is contained in the wiring, a high resistant Al3Ti is formed during heat treatment as in the case of the aforementioned reflow, so that the volume of Al in relative to the volume of wiring is substantially decreased, thus increasing the wire resistance. This problem of increase in wire resistance becomes more serious as the wiring becomes higher in integration and in fineness.
There is also proposed a method (Japanese Patent Unexamined Publication H/2-199838) which is substantially a combination of the method disclosed in Japanese Patent Unexamined Publication S/60-46024 and the method disclosed in Japanese Patent Unexamined Publication S/63-70455.
According to this method, the interior of contact hole is filled in advance with an Si film by making use of the Si-CVD technique, and then an Al film is substituted for the Si film, whereby making it possible to carry out the filling of a contact hole of high aspect ratio, any excessive Si film being absorbed by making use of a Ti film.
According to this method, it is possible to fill a contact hole of high aspect ratio with an Al film. The Al film is subsequently worked by means of RIE to form an Al wiring.
However, this method is accompanied with the following problems. Namely, the Al film to be obtained according to this method contains a product of high resistance such as Al3Ti, which may be formed through a reaction between Ti silicide to be formed through an absorption of the Al film by the Ti film and the Al film, or through a reaction between an excessive Ti film which has not been served for the absorption of the Si film and the Al film.
Therefore, when the Al film containing a product of such a high resistance is worked by means of RIE to form an Al wiring, an Al wiring 83 containing a high resistance product 87 on its upper surface as shown in FIG. 2A, or an Al wiring 83 containing a high resistance product 87 on its upper surface and side walls as shown in FIG. 2B would be obtained.
The Al wiring 83 containing such a high resistance product 87 is too high in resistance to use it as a fine wiring. The reference numeral 86 shown in these FIGS. 2A and 2B denotes a first wiring.
This invention has been accomplished under the aforementioned circumstances, and the objects of this invention is to provide a semiconductor device having a contact structure of high reliability that is formed in an insulating film provided with contact holes and wiring grooves.
Another object of this invention is to provide a method of manufacturing a semiconductor device having a contact structure of high reliability that is formed in an insulating film provided with contact holes and wiring grooves.
The present inventor has at first found out a method of manufacturing an Al damascene structure or an Al dual damascene structure, which is featured in that an Al film is substituted for an Si film at first, any superfluous portion of the Si film is allowed to be absorbed by a Ti film during or after the substitution, and reaction products which are high in resistance and formed between the Al film and Ti film or between the Ti film and Si film are removed by means of the CMP method. As matter of fact, it has been confirmed by the present inventor that the reaction products causing an increase in wire resistance can be easily removed, thus making it possible with this method to lower the resistance of the wiring.
It has been also found out by the present inventor that the aforementioned method is accompanied with various problems as explained below. Namely, the quantity of Si to be substituted becomes excessive depending on the layout of pattern at the occasion of carrying out the substitution between the Si film and the Al film after the interiors of the wiring groove and contact hole are filled with the Si film.
As a result, a long period of time is required for the substitution, thus lowering the throughput. Furthermore, a Si nodule tends to be partially developed, thus increasing the electric resistance of wiring if the nodule is formed on the wiring. The generation of the Al nodule may become a cause for generating a flaw in the subsequent CMP process. Namely, it has been found that the aforementioned method is accompanied with various problems to be solved before it is put into an actual use.
This invention has been accomplished with a view to solve the aforementioned problems.
[1] Namely, this invention provides; a method of manufacturing semiconductor device which comprises the steps of:
forming an insulating film on a semiconductor substrate provided with a conductive layer;
forming a contact hole through the insulating film to a depth reaching to the conductive layer and forming a wiring groove in the insulating film;
forming a substitutive film (a film to be substituted) so as to incompletely fill interiors of the contact hole and the wiring groove, but at least partially filling the interior of contact hole with the substitutive film;
forming a conductive film at a region comprising the contact hole and the wiring groove;
forming an absorption layer on the conductive film, and filling the interiors of the contact hole and the wiring groove with the conductive film by substituting the conductive film for the substitutive film and by allowing the substitutive film to be absorbed by the absorption layer under a heat treatment; and
removing a compound formed in the process of allowing the substitutive film to be absorbed by the absorption layer, and forming a plug comprising the conductive film in the contact hole as well as a wiring comprising the conductive film in the wiring groove by working the conductive film so as to selectively leave the conductive film in the interiors of the contact hole and the wiring groove.
It has been also found as a result of studies made by the present inventor that if the quantity of Ti is too large, a void is more likely to be formed in the Al film. This phenomenon can be ascribed to the fact that when the Si filled in the wiring groove or in the contact hole is absorbed by the upper Ti layer so as to be substituted by Al, a reaction layer formed as a result of reaction of Si with Ti gives a stress to the Al film.
Namely, an AlTi compound layer is formed at the interface of Al/Ti in the heat treatment for effecting the substitution between Si and Al, and at the same time, the Si diffused through the Al film is caused to react with Ti to form a TiSi compound layer, thus giving rise to the generation of void in the Al film due to stress exerted by the AlTi compound layer and the TiSi compound layer. In particular, the stress gradient that will be given by the AlTi compound to the Al film is relatively large, so that some measures are required to suppress the formation of the AlTi compound.
The dual damascene structure comprises an Al wiring in the lower layer thereof, so that when the Si filled in the upper wiring groove and contact hole is substituted by Al, the void may be generated in this lower Al wiring layer too. When the lower wiring is not formed with an Al wiring but with W, the void can be observed in the interior of the upper wiring groove. This pattern dependency of void may be attributed to the phenomenon that the void tends to generate at a location which minimizes the surface free energy of the void.
The void may become a cause for a disconnection of wiring and for a deterioration of electromigration resistance or stress migration resistance, and hence some measures are required to be taken to solve the problems in actual use.
Followings are specific embodiments of the aforementioned method [1] of manufacturing a semiconductor device.
(a) The wiring groove is formed after the contact hole is formed.
(b) A barrier film or a CMP stopper layer is formed after the contact hole is formed, and then the wiring groove is formed.
(c) The contact hole is formed after the wiring groove is formed.
(d) A barrier film or a CMP stopper layer is formed after the wiring groove is formed, and then the contact hole is formed.
(e) A barrier film or a CMP stopper layer is formed after the contact hole and the wiring groove are formed.
(f) The contact hole and the wiring groove are formed after a barrier film or a CMP stopper layer is formed on the insulating film.
[2] This invention further provides; a method of manufacturing semiconductor device which comprises the steps of:
forming a first insulating film on a semiconductor substrate provided with a conductive layer;
forming a contact hole through the first insulating film to a depth reaching to the conductive layer;
forming a substitutive film in an interior of contact hole;
forming a second insulating film all over an upper surface of the substrate;
forming a wiring groove in the second insulating film in a manner to connect it with the substitutive film;
forming a conductive film at a region comprising the contact hole and the wiring groove;
forming an absorption layer on the conductive film, and filling the interiors of the contact hole and the wiring groove with the conductive film by substituting the conductive film for the substitutive film and by allowing the substitutive film to be absorbed by the absorption layer under a heat treatment; and
removing a compound formed in the process of allowing the substitutive film to be absorbed by the absorption layer, and forming a plug comprising the conductive film in the contact hole as well as a wiring comprising the conductive film in the wiring groove by working the conductive film so as to selectively leave the conductive film in the interiors of the contact hole and the wiring groove.
Followings are specific embodiments of the aforementioned method [2] of manufacturing a semiconductor device.
(a) The contact hole is formed by means of RIE after an RIE stopper layer is formed on the first insulating film.
(b) A barrier film is formed after the contact hole is formed.
[3] This invention further provides; a method of manufacturing semiconductor device which comprises the steps of:
forming an insulating film on a semiconductor substrate provided with a conductive layer;
forming a contact hole through the insulating film to a depth reaching to the conductive layer;
forming a substitutive film at least in an interior of the contact hole;
forming a wiring groove in the insulating film;
forming a conductive film at a region comprising the contact hole and the wiring groove;
forming an absorption layer on the conductive film, and filling the interiors of the contact hole and the wiring groove with the conductive film by substituting the conductive film for the substitutive film and by allowing the substitutive film to be absorbed by the absorption layer under a heat treatment; and
removing a compound formed in the process of allowing the substitutive film to be absorbed by the absorption layer, and forming a plug comprising the conductive film in the contact hole as well as a wiring comprising the conductive film in the wiring groove by working the conductive film so as to selectively leave the conductive film in the interiors of the contact hole and the wiring groove.
Followings are a specific embodiment of the aforementioned method [3] of manufacturing a semiconductor device.
(a) The contact hole is formed after a CMP stopper layer is formed on the first insulating film.
Followings are specific embodiments of the aforementioned methods [1] to [3] of manufacturing a semiconductor device.
(a) A substitutive film is formed all over the upper surface of the substrate to such a thickness that the substitutive film overflows from the contact hole, and then the substitutive film is etched back so as to selectively leave the substitutive film in the interior of the contact hole.
(b) A substitutive film is formed by means of a CVD method all over the upper surface of the substrate to such a thickness that the substitutive film over-flows from the contact hole, and then the substitutive film is etched back so as to selectively leave the substitutive film in the interior of the contact hole.
(c) A substitutive film is formed by means of a CVD method all over the upper surface of the substrate to such a thickness that the substitutive film overflows from the contact hole, and then the substitutive film is etched back by means of a CDE etch-back method, an RIE etch-back method, a CMP method or at least two methods selected from these methods so as to selectively leave the substitutive film in the interior of the contact hole.
(d) The substitutive film is formed by means of a selective CVD method or a plating method.
(e) In subsequent to the formation of the absorption layer, the substrate is subjected to a heat treatment thereby to allow the substitutive film to be substituted by the conductive film and to allow the substitutive film to be absorbed by the absorption layer.
(f) In simultaneous with the formation of the absorption layer, the substrate is subjected to a heat treatment thereby to allow the substitutive film to be substituted by the conductive film and to allow the substitutive film to be absorbed by the absorption layer.
(g) The conductive film is formed by means of a sputtering method or a CVD method.
(h) The conductive film is formed by means of a reflow so as to cover a step portion formed by a formation of the wiring groove.
(i) The absorption layer is formed by means of a sputtering method or a CVD method.
(j) The absorption layer is formed without breaking vacuum after the conductive film is formed in a vacuum, or the absorption layer is formed after a native oxide film and/or impurities are removed subsequent to the formation of the conductive film in a vacuum.
(K) The removal of the absorption layer and the product, and the working of the conductive film are all performed by means of a CMP method, an RIE etch-back method, a CDE etch-back method, a wet etching method or a combination of at least two methods selected from these methods.
(l) The conductive film is formed of a material which exhibits a lower volume density when it is employed in a form of a non-crystalline structure as compared with when it is employed in a form of a crystalline structure.
(m) The conductive film is formed of a porous crystalline material or an amorphous material.
(n) The conductive film contains at least partially a crystal defect or a region containing a rare gas.
[4] This invention further provides; a semiconductor device which comprises:
a semiconductor substrate provided with a conductive layer;
an insulating film formed on the substrate and having a flat upper surface;
a plug and a wiring formed on the insulating film and filled in interiors of a contact hole connected with the conductive layer and of a wiring groove, respectively; and
a barrier film interposed between a side wall of the contact hole and the conductive layer, between a side wall of the wiring groove and the wiring, and between a bottom of the wiring groove and the wiring.
[5] This invention further provides; a semiconductor device which comprises:
a semiconductor substrate provided with a conductive layer;
an insulating film formed on the substrate and having a flat upper surface;
a plug and a wiring formed on the insulating film and filled in interiors of a contact hole connected with the conductive layer and of a wiring groove, respectively; and
a barrier film interposed between a side wall and bottom of the contact hole and the conductive layer, and between a side wall and bottom of the wiring groove and the wiring.
[6] This invention further provides; a semiconductor device which comprises:
a semiconductor substrate provided with a conductive layer;
an insulating film formed on the substrate and having a flat upper surface;
a plug and a wiring formed on the insulating film and filled in interiors of a contact hole connected with the conductive layer and of a wiring groove, respectively; and
a barrier film interposed between a side wall and bottom of the contact hole and the conductive layer.
[7] This invention further provides; a semiconductor device which comprises:
a semiconductor substrate provided with a conductive layer;
an insulating film formed on the substrate and having a flat upper surface;
a plug and a wiring formed on the insulating film and filled in interiors of a contact hole connected with the conductive layer and of a wiring groove, respectively; and
a barrier film interposed between a side wall and bottom of the wiring groove and the conductive layer.
Followings are specific embodiments of the aforementioned semiconductor devices [4] to [7].
(a) A CMP stopper layer or an insulating barrier film is formed on an entire surface of insulating film excluding a region where the contact hole and the wiring groove are located.
(b) A barrier film is formed on a surface of the wiring.
(c) The conductive layer, the wiring and the plug are all formed of the same material.
(d) The conductive layer, the wiring and the plug are all formed of Al, an Al alloy, Cu or a Cu alloy.
(e) The conductive layer, the wiring and the plug are all formed of Al, an Al alloy, Cu or a Cu alloy, and the barrier film is formed of a refractory metal or a refractory metal compound.
[8] This invention further provides; a method of manufacturing semiconductor device which comprises the steps of:
forming an insulating film on a semiconductor substrate provided with a conductive layer;
forming a contact hole through the insulating film to a depth reaching to the conductive layer and forming a wiring groove in the insulating film;
forming a substitutive film by means of a CVD method to a thickness which enables it to cover inner surfaces of the contact hole and the wiring groove and to incompletely fill interiors of the contact hole and the wiring groove;
filling almost entirely the interiors of the contact hole and the wiring groove with a conductive film;
forming an absorption layer on the conductive film;
filling the interiors of the contact hole and the wiring groove completely with the conductive film by substituting the conductive film for the substitutive film and by allowing the substitutive film to be absorbed by the absorption layer under a heat treatment; and
removing a compound formed in the process of allowing the substitutive film to be absorbed by the absorption layer, and forming a plug comprising the conductive film in the contact hole as well as a wiring comprising the conductive film in the wiring groove by working the conductive film so as to selectively leave the conductive film in the interiors of the contact hole and the wiring groove.
[9] This invention further provides; a method of manufacturing semiconductor device which comprises the steps of:
forming an insulating film on a semiconductor substrate provided with a conductive layer;
forming a contact hole through the insulating film to a depth reaching to the conductive layer and forming a wiring groove in the insulating film;
forming a substitutive film by means of a CVD method to a thickness which enables it to cover inner surfaces of the contact hole and the wiring groove and to incompletely fill interiors of the contact hole and the wiring groove;
filling almost entirely the interiors of the contact hole and the wiring groove with a conductive film;
forming an absorption layer on the conductive film, and filling the interiors of the contact hole and the wiring groove completely with the conductive film by substituting the conductive film for the substitutive film and by allowing the substitutive film to be absorbed by the absorption layer under a heat treatment; and
removing a compound formed in the process of allowing the substitutive film to be absorbed by the absorption layer, and forming a plug comprising the conductive film in the contact hole as well as a wiring comprising the conductive film in the wiring groove by working the conductive film so as to selectively leave the conductive film in the interiors of the contact hole and the wiring groove.
Followings are specific embodiments of the aforementioned methods [8] and [9] of manufacturing a semiconductor device.
(a) The conductive film is formed by means of a reflow method, a non-selective CVD method, a selective CVD method or a plating method, thereby filling almost entirely the interiors of the contact hole and the wiring groove with the conductive film.
(b) In subsequent to the formation of the conductive film by means of a sputtering method, the interiors of the contact hole and the wiring groove are filled almost entirely with the conductive film by means of a reflow method which enables the conductive film to be fluidized with heating.
(c) In subsequent to the formation of the conductive film by means of a sputtering method without heating, the conductive film is additionally formed by means of a sputtering method with heating, and then the interiors of the contact hole and the wiring groove are filled with the conductive film by means of a two-step reflow method which enables the conductive film to be fluidized.
(d) In subsequent to the formation of the conductive film by means of a directional sputtering method without heating, the conductive film is additionally formed by means of a sputtering method with heating, and then the interiors of the contact hole and the wiring groove are filled with the conductive film by means of a two-step reflow method which enables the conductive film to be fluidized.
(e) A barrier film is formed after the contact hole and the wiring groove are formed.
[10] This invention further provides; a method of manufacturing semiconductor device which comprises the steps of:
forming an insulating film on a semiconductor substrate provided with a conductive layer;
forming a contact hole through the insulating film to a depth reaching to the conductive layer and forming a wiring groove in the insulating film;
forming a substitutive film in the interiors of the contact hole and the wiring groove;
removing a native oxide film and/or impurities on a surface of the substitutive film;
forming a conductive film on a region comprising the contact hole and the wiring groove;
forming an absorption layer on the conductive film, and filling the interiors of the contact hole and the wiring groove with the conductive film by substituting the conductive film for the substitutive film and by allowing the substitutive film to be absorbed by the absorption layer under a heat treatment; and
removing a compound formed in the process of allowing the substitutive film to be absorbed by the absorption layer, and forming a plug comprising the conductive film in the contact hole as well as a wiring comprising the conductive film in the wiring groove by working the conductive film so as to selectively leave the conductive film in the interiors of the contact hole and the wiring groove.
Followings are specific embodiments of the aforementioned method [10] of manufacturing a semiconductor device.
(a) The native oxide film and/or impurities are removed by means of a wet etching, a physical etching or a chemical etching.
(b) The native oxide film and/or impurities are removed by means of a wet etching, and then the surface of the substitutive film is subjected to a hydrogen termination treatment.
(c) After the native oxide film and/or impurities are removed by means of a physical etching, the substrate is kept in a vacuum until the conductive film is formed.
(d) After the native oxide film and/or impurities are removed by means of a chemical etching, the substrate is kept in a vacuum until the conductive film is formed.
[11] This invention further provides; a method of manufacturing semiconductor device which comprises the steps of:
forming an insulating film on a semiconductor substrate provided with a conductive layer;
forming a contact hole through the insulating film to a depth reaching to the conductive layer and forming a wiring groove in the insulating film;
forming a substitutive film to such a thickness that the interiors of the contact hole and the wiring groove are filled with the substitutive film and the substitutive film overflows from the contact hole and from the wiring groove;
removing the substitutive film in a vacuum by means of an RIE etch-back method or a CDE etch-back method to such an extent that the substitutive film is left remained at least in the interiors of the contact hole and the wiring groove;
forming a conductive film on a region comprising the contact hole and the wiring groove without breaking vacuum;
forming an absorption layer on the conductive film, and filling the interiors of the contact hole and the wiring groove with the conductive film by substituting the conductive film for the substitutive film and by allowing the substitutive film to be absorbed by the absorption layer under a heat treatment; and
removing a compound formed in the process of allowing the substitutive film to be absorbed by the absorption layer, and forming a plug comprising the conductive film in the contact hole as well as a wiring comprising the conductive film in the wiring groove by working the conductive film so as to selectively leave the conductive film in the interiors of the contact hole and the wiring groove.
[12] This invention further provides; a method of manufacturing semiconductor device which comprises the steps of:
forming an insulating film on a semiconductor substrate provided with a conductive layer;
forming a contact hole through the insulating film to a depth reaching to the conductive layer and forming a wiring groove in the insulating film;
forming a substitutive film to such a degree that the interiors of the contact hole and the wiring groove are filled with the substitutive film;
forming a conductive film on a region comprising the contact hole and the wiring groove in a heated condition which enables a native oxide film formed on a surface of the substitutive film to be decomposed through a reaction between the conductive film and the substitutive film during the formation of the conductive film;
forming an absorption layer on the conductive film, and filling the interiors of the contact hole and the wiring groove with the conductive film by substituting the conductive film for the substitutive film and by allowing the substitutive film to be absorbed by the absorption layer under a heat treatment; and
removing a compound formed in the process of allowing the substitutive film to be absorbed by the absorption layer, and forming a plug comprising the conductive film in the contact hole as well as a wiring comprising the conductive film in the wiring groove by working the conductive film so as to selectively leave the conductive film in the interiors of the contact hole and the wiring groove.
Followings are a specific embodiment of the aforementioned method [12] of manufacturing a semiconductor device.
(a) The conductive film is formed by means of a thermal sputtering.
[13] This invention further provides; a method of manufacturing semiconductor device which comprises the steps of:
forming a conductive layer on a semiconductor substrate;
forming an insulating film to cover the conductive layer formed on the substrate;
forming a contact hole through the insulating film to a depth reaching to the conductive layer and forming a wiring groove in the insulating film;
removing a native oxide film and/or impurities on a surface of the substitutive film, which has been exposed at a bottom of the contact hole;
forming a substitutive film at least in the interiors of the contact hole;
forming a conductive film on a region comprising the contact hole and the wiring groove;
forming an absorption layer on the conductive film, and filling the interiors of the contact hole and the wiring groove with the conductive film by substituting the conductive film for the substitutive film and by allowing the substitutive film to be absorbed by the absorption layer under a heat treatment; and
removing a compound formed in the process of allowing the substitutive film to be absorbed by the absorption layer, and forming a plug comprising the conductive film in the contact hole as well as a wiring comprising the conductive film in the wiring groove by working the conductive film so as to selectively leave the conductive film in the interiors of the contact hole and the wiring groove.
Followings are specific embodiments of the aforementioned method [13] of manufacturing a semiconductor device.
(a) After the native oxide film and/or impurities are removed in a vacuum by means of a physical etching or a chemical etching employing a halogen gas as an etching gas, the substrate is kept in a vacuum until the substitutive film is formed.
(b) After the native oxide film and/or impurities are removed by means of a physical etching or a chemical etching employing a halogen gas as an etching gas, the conductive film is formed by making use of a single-wafer processing type CVD apparatus, wherein the entire process beginning from the removal of the native oxide film and/or impurities until the formation of the substitutive film is finished is performed in a vacuum so as to prevent a reoxidation of the surface of the conductive layer.
(c) After the native oxide film and/or impurities are removed by means of a physical etching or a chemical etching employing a halogen gas as an etching gas, the conductive film is formed by making use of a high-speed single-wafer processing type CVD apparatus, wherein the entire process beginning from the removal of the native oxide film and/or impurities until the formation of the substitutive film is finished is performed in a vacuum so as to prevent a reoxidation of the surface of the conductive layer.
(d) After the native oxide film and/or impurities are removed by means of a chemical etching employing a halogen gas as an etching gas, the conductive film is formed by making use of a batch type CVD apparatus, wherein the entire process beginning from the removal of the native oxide film and/or impurities until the formation of the substitutive film is finished is performed in a vacuum so as to prevent a reoxidation of the surface of the conductive layer.
(e) The native oxide film and/or impurities are removed in a vacuum by means of a reduction reaction employing a reducing agent.
(f) After the native oxide film and/or impurities are removed, a barrier film is formed.
[14] This invention further provides; a method of manufacturing semiconductor device which comprises a step of:
substituting a conductive film for a substitutive film in the interior of a contact hole and/or a wiring groove, the conductive film being formed in advance on the substitutive film, rendering the substitutive film to be absorbed by an absorption layer to form a compound, whereby filling the contact hole and/or the wiring groove with the conductive film; and
wherein the conductive film is formed to have a roughened surface whereby increasing a contact area thereof with the absorption layer.
Followings are a specific embodiment of the aforementioned method [14] of manufacturing a semiconductor device.
(a) The conductive film is formed in a heated condition thereby forming a roughened surface.
[15] This invention further provides; a method of manufacturing semiconductor device which comprises a step of:
substituting a conductive film for a substitutive film in the interior of a contact hole and/or a wiring groove, the conductive film being formed in advance on the substitutive film, and rendering the substitutive film to be absorbed by an absorption layer to form a compound, whereby filling the contact hole and/or the wiring groove with the conductive film; and
wherein the conductive film formed is heat-treated whereby rendering the element of the substitutive film to diffuse into the conductive film, and then the absorption layer formed subsequently is heat-treated whereby rendering the element diffused into the conductive film to be absorbed by the absorption layer.
[16] This invention further provides; a method of manufacturing semiconductor device which comprises a step of:
substituting a conductive film for a substitutive film in the interior of a contact hole and/or a wiring groove, the conductive film being formed in advance on the substitutive film, and rendering the substitutive film to be absorbed by an absorption layer to form a compound, whereby filling the contact hole and/or the wiring groove with the conductive film; and
wherein the conductive film and the absorption layer are successively formed and then heat-treated whereby rendering the element of the substitutive film in the conductive film to be absorbed by the absorption layer.
Followings are a specific embodiment of the aforementioned method [16] of manufacturing a semiconductor device.
(a) After the heat treatment, the heat treatment for rendering the element of the substitutive film in the conductive film to be absorbed by the absorption layer is performed at least once more.
[17] This invention further provides; a method of manufacturing semiconductor device which comprises the steps of:
forming an insulating film on a semiconductor substrate provided with a conductive layer;
forming a contact hole through the insulating film to a depth reaching to the conductive layer and forming a wiring groove in the insulating film;
forming a substitutive film at least in the interiors of the contact hole and the wiring groove;
forming a conductive film containing a plurality of absorption bodies on a region comprising the contact hole and the wiring groove;
filling the interiors of the contact hole and the wiring groove with the conductive film by substituting the conductive film for the substitutive film and by allowing the substitutive film to be absorbed by the absorption layer under a heat treatment; and
removing a compound formed in the process of allowing the substitutive film to be absorbed by the absorption layer, and forming a plug comprising the conductive film in the contact hole as well as a wiring comprising the conductive film in the wiring groove by working the conductive film so as to selectively leave the conductive film in the interiors of the contact hole and the wiring groove.
[18] This invention further provides; a method of manufacturing semiconductor device which comprises the steps of:
forming an insulating film on a semiconductor substrate provided with a conductive layer;
forming a contact hole through the insulating film to a depth reaching to the conductive layer;
forming a substitutive film in the interior of the contact hole;
forming a conductive film having at the bottom thereof a plurality of absorption bodies, the absorption bodies also formed on a region excluding the contact hole;
filling the interior of the contact hole with the conductive film by substituting the conductive film for the substitutive film and by allowing the substitutive film to be absorbed by the absorption layer under a heat treatment; and
removing a compound formed in the process of allowing the substitutive film to be absorbed by the absorption layer, and forming a plug comprising the conductive film in the contact hole by working the conductive film so as to selectively leave the conductive film in the interior of the contact hole.
[19] This invention further provides; a method of manufacturing semiconductor device which comprises the steps of:
forming an insulating film on a semiconductor substrate provided with a conductive layer;
forming a contact hole through the insulating film to a depth at least reaching to the conductive layer and forming a substitutive film in an interior of a wiring groove;
forming a conductive film having at the bottom thereof a plurality of absorption bodies, the absorption bodies also formed on a region excluding the contact hole;
filling the interiors of the contact hole and the wiring groove with the conductive film by substituting the conductive film for the substitutive film and by allowing the substitutive film to be absorbed by the absorption layer under a heat treatment; and
removing a compound formed in the process of allowing the substitutive film to be absorbed by the absorption layer, and forming a plug comprising the conductive film in the contact hole as well as a wiring comprising the conductive film in the wiring groove by working the conductive film so as to selectively leave the conductive film in the interiors of the contact hole and the wiring groove.
[20] This invention further provides; a method of manufacturing semiconductor device which comprises the steps of:
forming an insulating film on a semiconductor substrate provided with a conductive layer;
forming an absorption layer on the insulating film;
forming a contact hole through the insulating film to a depth at least reaching to the conductive layer and a wiring groove, and working the absorption layer to obtain a plurality of partitioned absorption bodies;
forming a substitutive film in the interiors of the contact hole and the wiring groove;
forming a conductive film in a region comprising the contact hole, the wiring groove and the plurality of absorption bodies;
filling the interiors of the contact hole and the wiring groove with the conductive film by substituting the conductive film for the substitutive film and by allowing the substitutive film to be absorbed by the absorption layer under a heat treatment; and
removing a compound formed in the process of allowing the substitutive film to be absorbed by the absorption layer, and forming a plug comprising the conductive film in the contact hole as well as a wiring comprising the conductive film in the wiring groove by working the conductive film so as to selectively leave the conductive film in the interiors of the contact hole and the wiring groove.
[21] This invention further provides; a method of manufacturing semiconductor device which comprises the steps of:
forming an insulating film on a semiconductor substrate provided with a conductive layer;
forming a contact hole through the insulating film to a depth reaching to the conductive layer and forming a wiring groove in the insulating film;
forming a substitutive film at least in the interiors of the contact hole and the wiring groove;
forming a conductive film not containing an absorption layer on a region comprising the contact hole and the wiring groove;
filling the interiors of the contact hole and the wiring groove with the conductive film by substituting the conductive film for the substitutive film and by allowing the substitutive film to be absorbed by the absorption layer under a heat treatment; and
removing a compound formed in the process of allowing the substitutive film to be absorbed by the absorption layer, and forming a plug comprising the conductive film in the contact hole as well as a wiring comprising the conductive film in the wiring groove by working the conductive film so as to selectively leave the conductive film in the interiors of the contact hole and the wiring groove.
Followings are specific embodiments of the aforementioned methods [20] and [21] of manufacturing a semiconductor device.
(a) The conductive film is formed in such a manner that a plurality of absorption bodies are existed in the same layer.
(b) The conductive film is formed by making use of a shadow mask in such a manner that a plurality of absorption bodies are existed at a desired location in the same layer.
(c) The conductive film is formed in such a manner that a plurality of absorption bodies are existed at a desired location in the same layer and at desired plural levels within the same layer.
(d) The conductive film is formed in such a manner that a plurality of absorption bodies are existed at a desired location in the same layer and at desired plural levels within the same layer, each absorption layer being horizontally off-set from another absorption layer disposed over or below the each absorption layer.
(e) The conductive film is formed by making use of a shadow mask in such a manner that a plurality of absorption bodies are existed at a desired location in the same layer and at desired plural levels within the same layer, each absorption layer being horizontally off-set from another absorption layer disposed over or below the each absorption layer.
(f) The plurality of absorption bodies contained in the conductive film are respectively formed as a laminate film constituting together with the conductive film a laminate layer.
(g) The quantity of the plurality of absorption bodies disposed over a layer containing a relatively large quantity of the substitutive film is made larger as compared with that of absorption bodies disposed over a layer containing a relatively small quantity of the substitutive film.
(h) The plurality of absorption bodies are formed by making use of ion-implanting.
(i) The absorption bodies are constituted by fine particles.
(j) The conductive film containing a plurality of absorption bodies therein is formed by depositing fine particles consisting of a constituent material of the conductive film and a constituent material of the absorption bodies on a region of substrate comprising the contact hole and the wiring groove.
(k) The conductive film containing a plurality of absorption bodies therein is formed by coating a dispersion containing fine particles consisting of a constituent material of the conductive film and a constituent material of the absorption bodies on a region of substrate comprising the contact hole and the wiring groove.
(l) The conductive film containing a plurality of absorption bodies therein is formed of a film comprising a mixture consisting of a constituent material of the conductive film and a constituent material of the absorption bodies.
(m) The conductive film containing a plurality of absorption bodies therein is formed of an amorphous film comprising a mixture consisting of a constituent material of the conductive film and a constituent material of the absorption bodies.
(o) The conductive film containing a plurality of absorption bodies therein is formed by means of sputtering method employing a first target consisting mainly of a constituent material of the conductive film and a second target consisting mainly of a constituent material of the absorption bodies.
(p) The conductive film containing a plurality of absorption bodies therein is formed by means of sputtering method employing a sputtering target comprising a mixture of a constituent material of the conductive film and a constituent material of the absorption bodies.
[22] This invention further provides; a method of manufacturing semiconductor device which comprises a step of:
substituting a conductive film for a substitutive film in the interior of a contact hole and/or a wiring groove, the conductive film being formed in advance on the substitutive film, and rendering the substitutive film to be absorbed by an absorption layer to form a compound, whereby filling the contact hole and/or the wiring groove with the conductive film; and
wherein the step is performed by repeating a heat treatment at least twice, each heat treatment being performed at a different temperature from each other, whereby rendering the element of the substitutive film to be substituted by the conductive film, and rendering the substitutive film to be absorbed by the absorption layer.
Followings are specific embodiments of the aforementioned method [22] of manufacturing a semiconductor device.
(a) The heat treatment is performed in such a manner that a temperature of the final heat treatment is the lowest among that of other heat treatment(s).
(b) The heat treatment is performed at a temperature which permits a formation of the compound as well at a temperature which does permit a formation of the compound.
[23] This invention further provides; a method of manufacturing semiconductor device which comprises a step of:
substituting a conductive film for a substitutive film in the interior of a contact hole and/or a wiring groove, the conductive film being formed in advance on the substitutive film, and rendering the substitutive film to be absorbed by an absorption layer to form a compound, whereby filling the contact hole and/or the wiring groove with the conductive film; and
wherein the step is performed at first by means of heat treatment, whereby rendering the element of the substitutive film to be substituted by the conductive film, and rendering the substitutive film to be absorbed by the absorption layer, whereby producing the compound, and then by annealing the conductive film.
[24] This invention further provides; a method of manufacturing semiconductor device which comprises a step of substituting a conductive film for a substitutive film in the interior of a contact hole and/or a wiring groove, the conductive film being formed in advance on the substitutive film, and rendering the substitutive film to be absorbed by an absorption layer to form a compound, whereby filling the contact hole and/or the wiring groove with the conductive film; and which is featured to include the steps of:
filling the interior of a contact hole and/or a wiring groove with a conductive film by substituting the conductive film formed on the substitutive film for the substitutive film filled in the interior of a contact hole and/or a wiring groove, and by rendering the substitutive film to be absorbed by a first absorption layer to form a first compound;
removing the first compound and the conductive film disposed on a region other than the contact hole and the wiring groove;
forming a second absorption layer on a surface of the conductive film left remained after the previous step;
forming a second compound by rendering the substitutive film left remained in the conductive film to be absorbed by the second absorption layer by making use of a heat treatment; and
removing the second absorption layer and the second compound.
[25] This invention further provides; a method of manufacturing semiconductor device which comprises a step of:
filling a contact hole and/or a wiring groove with a conductive film through a substitution/absorption treatment, the substitution/absorption treatment being performed by substituting the conductive film for a substitutive film in the contact hole and/or the wiring groove, the conductive film being formed in advance on the substitutive film, and at the same time, by rendering the substitutive film to be absorbed by an absorption layer to form a compound; and
wherein the step is performed by introducing into the conductive film an element which differs from constituent materials of the conductive film and the absorption layer during or after the substitution/absorption treatment.
Followings are specific embodiments of the aforementioned method [25] of manufacturing a semiconductor device.
(a) The conductive film is formed of a single conductive element.
(b) The element is an element which is capable of lowering the solid solution limit of the constituent material of the substitutive film in the conductive film after the substitution/absorption treatment, or an element which is capable of improving electromigration resistance or stress migration resistance of the conductive film.
(c) The element is an element which is capable of improving electromigration resistance and/or stress migration resistance of the conductive film after the substitution/absorption treatment.
(d) The element is introduced into the conductive film by forming a film containing the element on a surface of at least one of the substitutive film, the conductive film and the absorption layer.
(e) The element is introduced into the conductive film by employing at least one of the substitutive film, the conductive film and the absorption layer, each containing the element.
(f) The element is introduced into the conductive film by forming a film containing the element and then rendering the element to enter into the conductive film by making use of a heat treatment.
(g) The element is introduced into the conductive film by forming a film containing the element and then rendering the element to enter into the conductive film by making use of a heat treatment, and a barrier film is formed at an interface between the film containing the element and the insulating film so as to prevent the film containing the element from directly contacting with the insulating film in which the contact hole and/or the wiring groove is formed.
(h) The element is introduced into the conductive film by forming a film containing the element and then rendering the element to enter into the conductive film by making use of a heat treatment, and a barrier film is formed at an interface between the film containing the element and the insulating film so as to prevent the film containing the element from directly contacting with the insulating film in which the contact hole and/or the wiring groove is formed, the barrier film being selected from the group consisting of a mono-layer film (such as an SiN film, a TiN film, a TaN film or WN film); and a laminate film (such as a Tixe2x80x94Sixe2x80x94N film, a Wxe2x80x94Sixe2x80x94N film or Taxe2x80x94Sixe2x80x94N film).
[26] This invention further provides; a method of manufacturing semiconductor device which comprises a step of:
filling a contact hole and/or a wiring groove with a conductive film through a substitution/absorption treatment, the substitution/absorption treatment being performed by substituting the conductive film for a substitutive film in the contact hole and/or the wiring groove, the conductive film being formed in advance on the substitutive film, and by rendering the substitutive film to be absorbed by an absorption layer to form a compound; and
wherein a constituent material of the substitutive film to be combined with a constituent material of the absorption layer is selected so as to form the compound, and a diffusion velocity of the constituent material of the substitutive film in the conductive film at the substitution/absorption treatment temperature is higher than a diffusion velocity of the constituent material of the absorption layer in the conductive film.
Followings are specific embodiments of the aforementioned method [26] of manufacturing a semiconductor device.
(a) A compound comprising the constituent material of substitutive film and the constituent material of absorption layer is produced at a faster rate than a compound comprising the constituent material of conductive film and the constituent material of absorption layer.
(b) A combination between the constituent material of substitutive film and the constituent material of conductive film is selected so as to produce a eutectic in the substitution/absorption treatment.
[27] This invention further provides; a method of manufacturing semiconductor device which comprises a step of filling a contact hole and/or a wiring groove formed in the same insulating film with a conductive film through a substitution between the substitutive film and the conductive film formed on the substitutive film, and which is featured to include the steps of:
forming the conductive film in the interior of the wiring groove after the substitutive film is formed in the interior of the contact hole; and
filling a contact hole and/or a wiring groove with a conductive film by substituting the conductive film for the substitutive film and by rendering the substitutive film to precipitate on the surface of the conductive film through a heat treatment.
[28] This invention further provides; a method of manufacturing semiconductor device which comprises a step of filling a contact hole and/or a wiring groove formed in the same insulating film with a conductive film through a substitution between the substitutive film and the conductive film formed on the substitutive film, and which is featured to include the steps of:
forming the substitutive film in the interiors of the contact hole and the wiring groove;
forming the conductive film in a region comprising the contact hole and the wiring groove;
substituting the conductive film for the substitutive film and rendering the substitutive film to precipitate on the surface of the conductive film through a heat treatment; and
removing the substitutive film protruded from the wiring groove, whereby forming a plug comprising the conductive film in the contact hole and/or a wiring comprising the conductive film in the wiring groove.
[29] This invention further provides; a method of manufacturing semiconductor device which comprises a step of filling a contact hole and/or a wiring groove formed in the same insulating film with a conductive film through a substitution between the substitutive film and the conductive film formed on the substitutive film, and which is featured to include the steps of:
forming the substitutive film in the interiors of the contact hole and the wiring groove;
forming the conductive film in a region comprising the contact hole and the wiring groove;
forming a precipitation-promoting layer for precipitating the element of the substitutive film in a region neighboring to the conductive film;
substituting the conductive film for the substitutive film and rendering the substitutive film to precipitate on the surface of the precipitation-promoting layer through a heat treatment; and
removing the substitutive film protruded from the wiring groove, whereby forming a plug comprising the conductive film in the contact hole and/or a wiring comprising the conductive film in the wiring groove.
Followings are a specific embodiment of the aforementioned method [29] of manufacturing a semiconductor device.
(a) The precipitation-promoting layer is formed of the same element as that of the substitutive film.
[30] This invention further provides; a method of manufacturing semiconductor device which comprises a step of filling a contact hole and/or a wiring groove formed in the same insulating film with a conductive film through a substitution between the substitutive film and the conductive film formed on the substitutive film, and which is featured to include the steps of:
forming the substitutive film in the interiors of the contact hole and the wiring groove;
forming the conductive film in a region comprising the contact hole and the wiring groove;
forming a precipitation-promoting layer for precipitating the element of the substitutive film in the conductive film, the precipitation-promoting layer containing a rare gas, crystal defects or impurities;
substituting the conductive film for the substitutive film and rendering the substitutive film to precipitate on the surface of the precipitation-promoting layer through a heat treatment; and
removing the substitutive film protruded from the wiring groove, whereby forming a plug comprising the conductive film in the contact hole and/or a wiring comprising the conductive film in the wiring groove.
[31] This invention further provides; a method of manufacturing semiconductor device which comprises a step of filling a contact hole and/or a wiring groove formed with a conductive film through a substitution between the substitutive film formed in the contact hole and/or the wiring groove and the conductive film formed on the substitutive film, and which is featured to include the steps of:
substituting the conductive film for the substitutive film by making use of a heat treatment in a gaseous atmosphere containing a material capable of producing a compound with the substitutive film, and rendering the compound to precipitate at an interface between the conductive film and the wiring groove and/or at an interface between the contact hole and the wiring groove; and
removing the conductive film, the substitutive film and the compound which are protruded from the wiring groove.
Followings are a specific embodiment of the aforementioned method [31] of manufacturing a semiconductor device.
(a) The gaseous atmosphere contains N, O, H or at least two kinds of element selected from N, O and H.
[32] This invention further provides; a method of manufacturing semiconductor device which comprises a step of filling a contact hole and/or a wiring groove formed with a conductive film through a substitution between the substitutive film formed in the contact hole and/or the wiring groove and the conductive film formed on the substitutive film, and which is featured to include a step of:
substituting the conductive film for the substitutive film by making use of a heat treatment in a gaseous atmosphere containing a material capable of producing a compound with the substitutive film, and removing the substitutive film by making use of a gas of the compound to be formed between the substitutive film and the material.
Followings are a specific embodiment of the aforementioned method [32] of manufacturing a semiconductor device.
(a) The gaseous atmosphere contains F, Br, Cl, I or at least two kinds of element selected from F, Br, Cl and I.
(b) A combination of a constituent material of the substitutive film, a constituent material of conductive film and a constituent material of the gaseous atmosphere is selected such that a compound to be produced through a reaction between constituent materials of the substitution film and gaseous atmosphere can be produced at a lower temperature as that of a compound to be produced through a reaction between constituent materials of the substitution film and conductive film.
(c) The gaseous atmosphere contains an ionized gas.
(d) A combination between the constituent material of substitutive film and the constituent material of conductive film is selected so as to produce a eutectic in the heat treatment.
(e) The constituent material of conductive film is Cu or a Cu alloy, and the constituent material of substitutive film is W, Ta, Nb, Bi, Si, Sn or Ti.
[33] This invention further provides; a method of manufacturing semiconductor device which comprises a step of forming a laminated insulating structure comprising at least two insulating films, each insulating film being provided with a contact hole and a wiring groove, each deposited with a substitutive film in the interior thereof, the step comprises the sub-steps of:
filling an interior of wiring groove of the uppermost insulating film with among the wiring grooves formed in the insulating films;
forming a conductive film on the uppermost insulating film;
forming an absorption layer in the conductive film, and filling the interiors of the contact hole and the wiring groove with the conductive film by substituting the conductive film for the substitutive film and by allowing the substitutive film to be absorbed by the absorption layer under a heat treatment; and
removing a compound formed in the process of rendering the substitutive film to be absorbed by the absorption layer, and forming a plug comprising the conductive film in the contact hole as well as a wiring comprising the conductive film in the wiring groove by working the conductive film so as to selectively leave the conductive film in the interiors of the contact hole and the wiring groove.
Followings are specific embodiments of the aforementioned method [33] of manufacturing a semiconductor device.
(a) Each substitutive film filled in the wiring groove is connected with each other via the substitutive film filled in the contact hole.
(b) All of the substitutive films disposed within the insulating films of the laminated insulating structure are concurrently substituted by the conductive film by means of the heat treatment.
(c) Each substitutive film disposed within the insulating films of the laminated insulating structure is at least partially contacted with the absorption layer via the conductive film before the heat treatment.
(d) The substitutive film filled in the wiring groove formed in the uppermost insulating film of the laminated insulating structure is contacted with the absorption layer via the conductive film.
(e) The substitutive film is formed via a refractory metal film or via a high-melting point alloy film in the contact hole and the wiring groove formed in at least one of the insulating films of the laminated insulating structure before the heat treatment.
(f) A portion of the contact hole is not required to be employed in an electric circuit.
(g) The manufacturing method further comprises a step of forming an insulating film provided with a plurality of wiring grooves each filled with the substitutive film, which comprises the sub-steps of; forming a plurality of wiring grooves on the surface of the insulating film; forming the substitutive film all over the surface of the insulating film; and removing all of the substitutive film excluding those formed in a region of the plurality of wiring grooves.
[34] This invention further provides; a method of manufacturing semiconductor device which comprises the steps of:
forming a contact hole in an insulating film;
filling the contact hole with a plug containing a refractory metal;
forming a wiring groove in the insulating film;
forming a conductive film in a region including the wiring groove to a thickness, thereby allowing the conductive film to be protrude from the wiring groove;
removing the conductive film to an extent to allow the surface of the insulating film to be exposed, thereby filling the wiring groove with a wiring consisting of the conductive film; and
forming a high-melting point conductive film containing a refractory metal on the wiring.
Followings are specific embodiments of the aforementioned method [34] of manufacturing a semiconductor device.
(a) The wiring groove is formed in a region including the plug in a manner to allow the plug to be left in the interior of the wiring groove.
(b) The plug is formed by means of a selective CVD method in a process of filling the contact hole with the plug.
(c) A conductive film containing a refractory metal is formed to a height protruding from the contact hole in a region including the contact hole by means of a CVD method, and then a surface of the conductive film is etched back by means of a CMP method, a CDE etch-back method or an RIE etch-back method so as to fill the contact hole with a plug containing the refractory metal,
(d) A conductive film containing a refractory metal is formed as a plug in a region including the contact hole, and then the conductive film is fluidized by means of a reflow method so as to fill the wiring groove with the conductive film.
(e) The wiring groove is filled with a substitutive film, a conductive film is deposited on the substitutive film, and then the substitutive film is substituted by the conductive film, whereby forming the conductive film in a region including the wiring groove to a height protruding from the wiring groove.
(f) The plug is directly contacted with the high-melting point conductive film.
(g) A treatment for removing a native oxide film by means of a physical etching or a wet etching is performed prior to the formation of the high-melting point conductive film.
(h) The plug is a tungsten plug.
[35] This invention further provides; a method of manufacturing semiconductor device which comprises a step of:
filling a contact hole and/or a wiring groove with a conductive film by substituting the conductive film for a substitutive film in the contact hole and/or the wiring groove, the conductive film being formed in advance on the substitutive film, and by rendering the substitutive film to be absorbed by an absorption layer; and
wherein the absorption layer, a compound formed in the above process of absorbing the substitutive film by the absorption layer, and the conductive film are successively removed.
Followings are specific embodiments of the aforementioned method [35] of manufacturing a semiconductor device.
(a) The absorption layer, the compound and the conductive film are removed by means of a CMP method.
(b) The absorption layer is removed by means of a wet etching, a CDE etch-back method or an RIE etch-back method, and the compound and the conductive film are removed by means of a CMP method.
(c) The absorption layer and the compound are removed by means of a wet etching, a CDE etch-back method or an RIE etch-back method, and the conductive film is removed by means of a CMP method.
(d) The absorption layer, the compound and the conductive film are removed by means a wet etching, a CDE etch-back method or an RIE etch-back method.
[36] This invention further provides; a method of manufacturing semiconductor device which comprises the steps of:
forming an insulating film on a semiconductor substrate provided with a conductive layer;
forming a contact hole through the insulating film to a depth reaching to the conductive layer and forming a wiring groove in the insulating film;
forming a substitutive film containing a diffusion-promoting agent in the contact hole and/or the wiring groove;
forming a conductive film at a region comprising the contact hole and the wiring groove;
forming an absorption layer on the conductive film, and filling the interiors of the contact hole and the wiring groove with the conductive film by substituting the conductive film for the substitutive film and by allowing the substitutive film to be absorbed by the absorption layer under a heat treatment; and
removing a compound formed in the process of allowing the substitutive film to be absorbed by the absorption layer, and forming a plug comprising the conductive film in the contact hole as well as a wiring comprising the conductive film in the wiring groove by working the conductive film so as to selectively leave the conductive film in the interiors of the contact hole and the wiring groove;
the diffusion-promoting agent functioning to promote an mutual diffusion between the substitutive film and the conductive film.
Followings are a specific embodiment of the aforementioned method [36] of manufacturing a semiconductor device.
(a) The diffusion-promoting agent is formed of boron, the conductive film is formed of an amorphous silicon film, the absorption layer is formed of titanium, and the compound is titanium silicide.
[37] This invention further provides; a method of manufacturing semiconductor device which comprises the steps of:
forming an insulating film on a semiconductor substrate provided with a conductive layer;
forming a contact hole through the insulating film to a depth reaching to the conductive layer and forming a wiring groove in the insulating film;
forming a substitutive film containing a diffusion-inhibiting agent in the contact hole and/or the wiring groove;
forming a conductive film at a region comprising the contact hole and the wiring groove;
forming an absorption layer on the conductive film, and filling the interiors of the contact hole and the wiring groove with the conductive film by substituting the conductive film for the substitutive film and by allowing the substitutive film to be absorbed by the absorption layer under a heat treatment; and
removing a compound formed in the process of allowing the substitutive film to be absorbed by the absorption layer, and forming a plug comprising the conductive film in the contact hole as well as a wiring comprising the conductive film in the wiring groove by working the conductive film so as to selectively leave the conductive film in the interiors of the contact hole and the wiring groove;
the diffusion-inhibiting agent functioning to react with the absorption film to form a diffusion-inhibiting film to inhibit the absorption film from diffusing into the conductive film, and the location of the diffusion-inhibiting film being at or near an interface between the absorption film and the conductive film.
Followings are specific embodiments of the aforementioned method [37] of manufacturing a semiconductor device.
(a) The diffusion-inhibiting agent is formed of boron, the conductive film is formed of an amorphous silicon film, the absorption layer is formed of titanium, the compound is titanium silicide, and the diffusion-inhibiting film is a titanium boride film.
(b) The substitutive film is formed by means of a CVD method employing a mixed gas containing plural kinds of feed gas.
(c) As the substitutive film, a boron-containing amorphous silicon film is formed by means of a CVD method employing a mixed gas containing disilane gas and diborane gas.
(d) As the substitutive film, a boron-containing amorphous silicon film is formed by means of a CVD method employing a mixed gas containing disilane gas and diborane gas at a temperature range which does not cause any deformation of the plug due to a thermal stress.
(e) As the substitutive film, a boron-containing amorphous silicon film is formed by means of a CVD method employing a mixed gas containing disilane gas and diborane gas at a temperature of not more than 400xc2x0 C. which does not cause any deformation of the plug due to a thermal stress.
[38] This invention further provides; a method of manufacturing semiconductor device which comprises the steps of:
forming an insulating film on a semiconductor substrate provided with a conductive layer;
forming a contact hole through the insulating film to a depth reaching to the conductive layer and forming a wiring groove in the insulating film;
forming a substitutive film in the contact hole and the wiring groove;
successively forming an absorption layer and a conductive film at a region comprising the contact hole and the wiring groove;
filling the interiors of the contact hole and the wiring groove with the conductive film by substituting the conductive film for the substitutive film and by allowing the substitutive film to be absorbed by the absorption layer under a heat treatment; and
removing a compound formed in the process of allowing the substitutive film to be absorbed by the absorption layer, and forming a plug comprising the conductive film in the contact hole as well as a wiring comprising the conductive film in the wiring groove by working the conductive film so as to selectively leave the conductive film in the interiors of the contact hole and the wiring groove.
[39] This invention further provides; a method of manufacturing semiconductor device which comprises the steps of:
forming an insulating film on a semiconductor substrate provided with a conductive layer;
forming a contact hole through the insulating film to a depth reaching to the conductive layer;
forming a substitutive film in the contact hole;
successively forming an absorption layer and a conductive film at a region comprising the contact hole;
filling the interior of the contact hole with the conductive film by substituting the conductive film for the substitutive film and by allowing the substitutive film to be absorbed by the absorption layer under a heat treatment; and
removing a compound formed in the process of allowing the substitutive film to be absorbed by the absorption layer, and forming a plug comprising the conductive film in the contact hole by working the conductive film so as to selectively leave the conductive film in the interior of the contact hole.
[40] This invention further provides; a method of manufacturing semiconductor device which comprises the steps of:
forming an insulating film on a semiconductor substrate provided with a conductive layer;
forming a contact hole through the insulating film to a depth reaching to the conductive layer and forming a wiring groove in the insulating film;
forming a substitutive film in the contact hole and/or the wiring groove;
forming a conductive film at a region comprising the contact hole and the wiring groove;
forming a diffusion-inhibiting layer on the conductive film;
forming an absorption layer on the diffusion-inhibiting layer and filling the interiors of the contact hole and the wiring groove with the conductive film by substituting the conductive film for the substitutive film and by allowing the substitutive film to be absorbed by the absorption layer under a heat treatment; and
forming a plug comprising the conductive film in the contact hole as well as a wiring comprising the conductive film in the wiring groove by working the conductive film so as to selectively leave the conductive film in the interiors of the contact hole and the wiring groove.
[41] This invention further provides; a method of manufacturing semiconductor device which comprises the steps of:
forming an insulating film on a semiconductor substrate provided with a conductive layer;
forming a contact hole through the insulating film to a depth reaching to the conductive layer and forming a wiring groove in the insulating film;
forming a substitutive film in the contact hole and/or the wiring groove;
forming a conductive film at a region comprising the contact hole and the wiring groove;
forming an absorption layer on the conductive film and forming a diffusion-inhibiting layer and filling the interiors of the contact hole and the wiring groove with the conductive film by substituting the conductive film for the substitutive film and by allowing the substitutive film to be absorbed by the absorption layer under a heat treatment; and
forming a plug comprising the conductive film in the contact hole as well as a wiring comprising the conductive film in the wiring groove by working the conductive film so as to selectively leave the conductive film in the interiors of the contact hole and the wiring groove;
the heat treatment being performed at first at a lower temperature thereby to form the diffusion-inhibiting layer, and then at a higher temperature thereby to accelerate the absorption of the substitutive film by the absorption layer.
[42] This invention further provides; a method of manufacturing semiconductor device which comprises the steps of:
forming an insulating film on a semiconductor substrate provided with a conductive layer;
forming a contact hole through the insulating film to a depth reaching to the conductive layer and forming a wiring groove in the insulating film;
forming a substitutive film containing a diffusion-promoting agent in the contact hole and/or the wiring groove;
forming a conductive film at a region comprising the contact hole and the wiring groove;
forming an absorption layer on the conductive film, and filling the interiors of the contact hole and the wiring groove with the conductive film by substituting the conductive film for the substitutive film and by allowing the substitutive film to be absorbed by the absorption layer under a heat treatment; and
removing a compound formed in the process of allowing the substitutive film to be absorbed by the absorption layer, and forming a plug comprising the conductive film in the contact hole as well as a wiring comprising the conductive film in the wiring groove by working the conductive film so as to selectively leave the conductive film in the interiors of the contact hole and the wiring groove;
a combination of the temperature and time of the heat treatment being controlled such that the total of the resistive component of the conductive film originating from the constituent material of the substitutive film remaining in the conductive film filled in the contact hole and wiring groove and the resistive component of the conductive film originating from the constituent material of the absorption layer remaining in the conductive film filled in the contact hole and wiring groove becomes minimum or nearly minimum.
[43] This invention further provides; a method of manufacturing semiconductor device which comprises a step of:
filling a contact hole and/or a wiring groove with a conductive film through a substitution/absorption treatment, the substitution/absorption treatment being performed by substituting the conductive film for a substitutive film in the contact hole and/or the wiring groove, the conductive film being formed in advance on the substitutive film, and by rendering the substitutive film to be absorbed by an absorption layer to form a compound; and
wherein the substitution/absorption treatment is performed in a gaseous atmosphere which enables the constituent material of the absorption layer that has been diffused through the conductive film to be discharged out of the conductive film; or an additional heat treatment is performed after the substitution/absorption treatment in a gaseous atmosphere which enables the constituent material of the absorption layer that is remained in the conductive film to be discharged out of the conductive film.
[44] This invention further provides; a method of manufacturing semiconductor device which comprises a step of:
filling a contact hole and/or a wiring groove with a conductive film by substituting the conductive film formed on a substitutive film for the substitutive film filled in the contact hole and/or the wiring groove and by rendering the substitutive film to be absorbed by an absorption layer; and
wherein a compound formed in the absorption of the substitutive film by the absorption layer is removed, and the conductive film is worked to selectively leave the conductive film in the interiors of the contact hole and the wiring groove, whereby forming a plug comprising the conductive film in the contact hole as well as a wiring comprising the conductive film in the wiring groove; and then a heat treatment is performed in a gaseous atmosphere which enables the constituent material of the absorption layer that is remained in the conductive film to be discharged out of the conductive film.
Followings are a specific embodiment of the aforementioned methods [42] to [44] of manufacturing a semiconductor device.
(a) The gaseous atmosphere contains N, O, H, C, B or at least two kinds of element selected from N, O, H, C and B.
[45] This invention further provides; a method of manufacturing semiconductor device which comprises a step of:
filling a contact hole and/or a wiring groove with a conductive film through a substitution/absorption treatment, the substitution/absorption treatment being performed by substituting the conductive film for a substitutive film in the contact hole and/or the wiring groove, the conductive film being formed in advance on the substitutive film, and by rendering the substitutive film to be absorbed by an absorption layer to form a compound; and
wherein the compound is removed after the substitution/absorption treatment; the conductive film is worked to selectively leave the conductive film in the interiors of the contact hole and the wiring groove, whereby forming a plug comprising the conductive film in the contact hole as well as a wiring comprising the conductive film in the wiring groove; then the conductive film is heat-treated at a temperature which is higher than that of solid solution limit at the solid solution concentration of constituent material of the absorption layer remained in the conductive film and which is lower than the substitution/absorption treatment temperature, after which the conductive film is annealed, whereby discharging the constituent material of the absorption layer remained in the conductive film to be discharged out of the conductive film; and a reaction product layer containing the constituent material of the absorption layer that has been discharged on the surface of the conductive film is removed.
Followings are a specific embodiment of the aforementioned methods [42], [43] and [45] of manufacturing a semiconductor device.
(a) The reaction product layer is removed by means of an RIE etch-back method or a CMP method.
[46] This invention further provides; a method of manufacturing semiconductor device which comprises a step of:
filling a contact hole and/or a wiring groove with a conductive film through a substitution/absorption treatment, the substitution/absorption treatment being performed by substituting the conductive film for a substitutive film in the contact hole and/or the wiring groove, the conductive film being formed in advance on the substitutive film, and by rendering the substitutive film to be absorbed by an absorption layer to form a compound; and
wherein the conductive film is formed on the substitutive film to such a thickness which is sufficient enough to reduce the quantity of constituent material of the absorption layer diffusing into the interior of the contact hole and wiring groove at the occasion of the substitution/absorption treatment.
[47] This invention further provides; a method of manufacturing semiconductor device which comprises a step of filling a contact hole and/or a wiring groove formed with a conductive film through a substitution between a substitutive film and the conductive film formed on the substitutive film, and which is featured to include the steps of:
forming the substitutive film in the interiors of the contact hole and the wiring groove;
forming the conductive film in a region comprising the contact hole and the wiring groove;
forming an absorption layer on the conductive film;
forming a film on the absorption layer, which is capable of giving a compressive stress in conformity with a tensile stress in the direction of the conductive film due to a voluminal change of the absorption layer;
substituting the conductive film for the substitutive film and allowing the substitutive film to be absorbed by the absorption layer under a heat treatment; and
removing the substitutive film and absorption layer disposed higher than the wiring groove, whereby forming a plug comprising the conductive film in the contact hole as well as a wiring comprising the conductive film in the wiring groove.
[48] This invention further provides; a method of manufacturing semiconductor device which comprises a step of filling a contact hole and/or a wiring groove formed with a conductive film through a substitution between a substitutive film and the conductive film formed on the substitutive film, and which is featured to include the steps of:
forming the substitutive film in the interiors of the contact hole and the wiring groove;
forming the conductive film in a region comprising the contact hole and the wiring groove;
forming a film in the conductive film, which enables the constituent elements of the substitutive film and conductive film to pass therethrough and is capable of alleviating a tensile stress in the direction of the conductive film due to a voluminal change of the absorption layer;
forming an absorption layer on the conductive film;
substituting the conductive film for the substitutive film and allowing the substitutive film to be absorbed by the absorption layer under a heat treatment; and
removing the substitutive film and absorption layer disposed higher than the wiring groove, whereby forming a plug comprising the conductive film in the contact hole as well as a wiring comprising the conductive film in the wiring groove.
[49] This invention further provides; a method of manufacturing semiconductor device which comprises a step of filling a contact hole and/or a wiring groove formed with a conductive film through a substitution between a substitutive film and the conductive film formed on the substitutive film, and which is featured to include the steps of:
forming the substitutive film in the interiors of the contact hole and the wiring groove;
forming the conductive film in a region comprising the contact hole and the wiring groove;
forming an absorption film which exhibits little change or shrinkage in volume in a heat treatment for substitution where the substitutive film is rendered to be absorbed by the absorption film;
substituting the conductive film for the substitutive film and allowing the substitutive film to be absorbed by the absorption layer under a heat treatment; and
removing the substitutive film and absorption layer disposed higher than the wiring groove, whereby forming a plug comprising the conductive film in the contact hole as well as a wiring comprising the conductive film in the wiring groove.
In the aforementioned method of manufacturing a semiconductor device, the constituent material of the conductive film may be selected from Al and an Al alloy; the constituent material of the substitutive film may be selected from Si and Ge; and the constituent material of the absorption layer may be selected from Ti, Hf, V, Zr, W, Co, Ni, Pd and Fe.
[50] This invention further provides; a semiconductor device which comprises:
a semiconductor substrate;
an insulating film formed on the substrate and having a recessed portion; and
a conductive film formed in the recessed portion;
the conductive film containing a trace amount of a substance having a lower melting point than that of element mainly constituting the conductive film.
[51] This invention further provides; a semiconductor device which comprises:
a semiconductor substrate;
an insulating film formed on the substrate and having a recessed portion;
a thin film formed at least partially on an inner surface of the recessed portion and consisting of a barrier metal or a material exhibiting a higher surface energy than that of the insulating film; and
a conductive film formed in the recessed portion;
the conductive film containing a substance having a lower melting point than that of element mainly constituting the conductive film, a quantity of the substance being not more than a maximum concentration thereof that can be solid-solubilized.
Followings are specific embodiments of the aforementioned semiconductor devices [50] and [51].
(a) The maximum concentration of the substance that can be solid-solubilized is selected such that, when the element mainly constituting the conductive film and the lower melting point substance are in a state of solid-liquid equilibrium, it corresponds to a maximum concentration of the lower melting point substance in the solid phase consisting of the element and the lower melting point substance which is equilibrated with the liquid phase.
(b) The element mainly constituting the conductive film and the substance having a lower melting point than that of element mainly constituting the conductive film are capable of forming an eutectic.
(c) The element mainly constituting the conductive film is at least one element selected from the group consisting of Al, Cu, Ag, W, Si, Ge and SiGe.
(d) The substance having a lower melting point than that of element mainly constituting the conductive film (hereinafter referred to as a lower melting point substance) is at least one element selected from the group consisting of Sn, Ga, Hg and Ge, if the element mainly constituting the conductive film is Al; the lower melting point substance is Bi, if the element mainly constituting the conductive film is Cu; the lower melting point substance is Tl, if the element mainly constituting the conductive film is Ag; the lower melting point substance is at least one element selected from the group consisting of Ge, Ga, Bi, Sn and Ce, if the element mainly constituting the conductive film is W; the lower melting point substance is at least one element selected from the group consisting of Zn, In, Cd, Zg, Sn and Al, if the element mainly constituting the conductive film is Si, Ge or SiGe.
[52] This invention further provides; a method of manufacturing semiconductor device which comprises the steps of:
forming an insulating film on a semiconductor substrate;
forming a recessed portion in the insulating film;
forming a liquid phase containing a conductive element and a substance having a lower melting point than that of the conductive element in the recessed portion;
forming a conductive film at least in the recessed portion by shifting the composition of the liquid phase from an equilibrium composition to a composition where the conductive element is excessive, thereby precipitating the conductive element; and
removing all of materials from the surface of the insulating film excluding those formed on the recessed portion.
[53] This invention further provides; a method of manufacturing semiconductor device which comprises the steps of:
forming an insulating film on a semiconductor substrate;
forming a recessed portion in the insulating film;
forming a barrier metal or a material exhibiting a higher surface energy than that of the insulating film forming a liquid phase containing a conductive element and a substance having a lower melting point than that of the conductive element in the insulating film;
forming a conductive film at least in the recessed portion by shifting the composition of the liquid phase from an equilibrium composition to a composition where the conductive element is excessive, thereby precipitating the conductive element; and
removing all of materials from the surface of the is insulating film excluding those formed on the recessed portion.
Followings are specific embodiments of the aforementioned methods [52] and [53] of manufacturing a semiconductor device.
(a) The step of forming a liquid phase containing a conductive element and a substance having a lower melting point than that of the conductive element in the recessed portion is performed in such a manner that a solid phase alloy layer containing the conductive element and the substance having a lower melting point than that of the conductive element is formed in the recessed portion, and then the solid phase alloy layer is heated to melt.
(b) The step of forming a liquid phase containing a conductive element and a substance having a lower melting point than that of the conductive element in the recessed portion is performed in such a manner that a layer of the substance having a lower melting point than that of the conductive element is formed at least in the recessed portion, a layer of the conductive element is formed at least in the recessed portion, and then the layer of the substance having a lower melting point is heated to form a melt, thereby allowing the conductive element to be diffused in the melt.
(c) The step of forming a liquid phase containing a conductive element and a substance having a lower melting point than that of the conductive element in the recessed portion is performed in such a manner that a layer of the substance having a lower melting point than that of the conductive element is formed at least in the recessed portion, and then the layer of the substance having a lower melting point is heated to form a liquid phase, into which the conductive element to introduced.
(d) The step of forming a liquid phase containing a conductive element and a substance having a lower melting point than that of the conductive element in the recessed portion is performed in such a manner that a melt of the substance having a lower melting point than that of the conductive element, or a melt consisting of the conductive element and the substance having a lower melting point is forced to fill in the recessed portion under pressure.
(e) The step of shifting the composition of the liquid phase from an equilibrium composition to a composition where the conductive element is excessive thereby to precipitate the conductive element is performed in such a manner that a process of lowering the temperature of the liquid phase, or a process of lowering the temperature of the liquid phase to a solid-liquid two-phase temperature region and maintaining this temperature is performed at least once.
(f) The step of shifting the composition of the liquid phase from an equilibrium composition to a composition where the conductive element is excessive thereby to precipitate the conductive element comprises the sub-steps of; lowering the temperature of the liquid phase to a solid-liquid two-phase temperature region, maintaining this temperature thereby allowing the conductive element to precipitate; increasing the temperature of the phase to restore the liquid phase; introducing the conductive element into the liquid phase; and lowering the liquid phase; the sub-steps being performed at least once.
(g) The step of shifting the composition of the liquid phase from an equilibrium composition to a composition where the conductive element is excessive thereby to precipitate the conductive element includes a step of heat treatment in an atmosphere containing at least one element selected from the group consisting of N, O and H.
(h) The step of shifting the composition of the liquid phase from an equilibrium composition to a composition where the conductive element is excessive thereby to precipitate the conductive element includes a step of heat treatment in an atmosphere enabling a formation of a gas phase compound containing the substance having a lower melting point, and a step of removing the gas phase compound.
(i) The step of removing all of materials from the surface of the insulating film excluding those formed on the recessed portion comprises the sub-steps of; introducing a gas containing a halogen to form a halide; and removing the halide.
(j) The step of removing all of materials from the surface of the insulating film excluding those formed on the recessed portion comprises the sub-steps of; introducing a gas containing at least one element selected from chlorine, fluorine, iodine and bromine to form a chloride, fluoride, iodide or bromide; and removing the halide.
[54] This invention further provides; a method of manufacturing semiconductor device which comprises the steps of:
forming an insulating film on a semiconductor substrate;
forming a recessed portion in the insulating film;
forming a liquid phase containing a conductive element and a substance having a lower melting point than that of the conductive element in the recessed portion;
forming a conductive film in the recessed portion by shifting the composition of the liquid phase from an equilibrium composition to a composition where the conductive element is excessive, thereby precipitating the conductive element; and
removing all of materials from the surface of the insulating film excluding those formed on the recessed portion;
an additive element is introduced into the conductive element during or after the precipitation of the conductive element.
Followings are specific embodiments of the aforementioned method [54] of manufacturing a semiconductor device.
(a) The conductive element is formed of a single kind of element.
(b) The additive element is an element which is capable of improving the electromigration resistance or stress migration resistance of the conductive film after the precipitation.
(c) The additive element is an element which is capable of lowering the solid solution limit of the substance having a lower melting point after the precipitation.
Additional object and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The object and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the appended claims.